Re: [PATCH v3 2/3] qapi: improve specificity of type/member descriptions

[Markus Armbruster <armbru@redhat.com>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> On Mon, Apr 24, 2023 at 01:38:21PM +0200, Markus Armbruster wrote:
>> Daniel P. Berrangé <berrange@redhat.com> writes:
>> 
>> > When describing member types always include the context of the
>> > containing type. Although this is often redundant, in some cases
>> > it will help to reduce ambiguity.
>> 
>> This is no longer true.  It was in v2.  Suggest:
>> 
>>   Error messages describe object members, enumeration values, features,
>>   and variants like ROLE 'NAME', where ROLE is "member", "value",
>>   "feature", or "branch", respectively.  When the member is defined in
>>   another type, e.g. inherited from a base type, we add "of type
>>   'TYPE'".  Example: test case struct-base-clash-deep reports a member
>>   of type 'Sub' clashing with a member of its base type 'Base' as
>> 
>>       struct-base-clash-deep.json: In struct 'Sub':
>>       struct-base-clash-deep.json:10: member 'name' collides with member 'name' of type 'Base'
>> 
>>   Members of implicitly defined types need special treatment.  We don't
>>   want to add "of type 'TYPE'" for them, because their named are made up
>>   and mean nothing to the user.  Instead, we describe members of an
>>   implicitly defined base type as "base member 'NAME'", and command and
>>   event parameters as "parameter 'NAME'".  Example: test case
>>   union-bad-base reports member of a variant's type clashing with a
>>   member of its implicitly defined base type as
>> 
>>       union-bad-base.json: In union 'TestUnion':
>>       union-bad-base.json:8: member 'string' of type 'TestTypeA' collides with base member 'string'
>> 
>>   The next commit will permit unions as variant types.  "base member
>>   'NAME' would then be ambigious: is it the union's base, or is it the
>>   union's variant's base?  One of its test cases would report a clash
>>   between two such bases as "base member 'type' collides with base
>>   member 'type'".  Confusing.
>> 
>>   Refine the special treatment: add "of TYPE" even for implicitly
>>   defined types, but massage TYPE and ROLE so they make sense for the
>>   user.
>> 
>> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
>> > ---
>> >  scripts/qapi/schema.py | 9 +++++++--
>> >  1 file changed, 7 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
>> > index 207e4d71f3..da04b97ded 100644
>> > --- a/scripts/qapi/schema.py
>> > +++ b/scripts/qapi/schema.py
>> > @@ -697,6 +697,7 @@ def connect_doc(self, doc):
>> >  
>> >      def describe(self, info):
>> >          role = self.role
>> > +        meta = 'type'
>> >          defined_in = self.defined_in
>> >          assert defined_in
>> >  
>> > @@ -708,13 +709,17 @@ def describe(self, info):
>> >                  # Implicit type created for a command's dict 'data'
>> >                  assert role == 'member'
>> >                  role = 'parameter'
>> > +                meta = 'command'
>> > +                defined_in = defined_in[:-4]
>> >              elif defined_in.endswith('-base'):
>> >                  # Implicit type created for a union's dict 'base'
>> >                  role = 'base ' + role
>> > +                defined_in = defined_in[:-5]
>> >              else:
>> >                  assert False
>> > -        elif defined_in != info.defn_name:
>> > -            return "%s '%s' of type '%s'" % (role, self.name, defined_in)
>> > +
>> > +        if defined_in != info.defn_name:
>> > +            return "%s '%s' of %s '%s'" % (role, self.name, meta, defined_in)
>> >          return "%s '%s'" % (role, self.name)
>> 
>> Since I rewrote both the patch and the commit message, would you like me
>> to take the blame and claim authorship?
>
> Yes, I should have credited you as the author here since it was just
> taking your proposed code. The suggested commit message looks fine too

Thanks!  May I add your R-by in my tree?